Kinetics and mechanism of the nickel electrode : I. Acid solutions containing a high concentration of chloride and nickel ions

The kinetics of the Ni electrode in acid solutions with a high chloride ion concentration has been investigated in the range of 25–75°C. Dissolution occurs uniformly only at low anodic potentials. When the latter exceeds a critical value, Ecrit, net localized metal corrosion takes place. The <mat...

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Detalles Bibliográficos
Autores principales: Vilche, Jorge Roberto, Arvia, Alejandro Jorge
Formato: Articulo
Lenguaje:Inglés
Publicado: 1975
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Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/121739
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Sumario:The kinetics of the Ni electrode in acid solutions with a high chloride ion concentration has been investigated in the range of 25–75°C. Dissolution occurs uniformly only at low anodic potentials. When the latter exceeds a critical value, Ecrit, net localized metal corrosion takes place. The <math><mtext>E</mtext><mtext>ln</mtext><mtext> i</mtext><msub><mi></mi><mn>a</mn></msub></math> plot at E < Ecrit corresponds to a curve approaching two limiting slopes, namely, <math><mtext>2RT</mtext><mtext>3F</mtext></math> at (<math><mtext>E − E</mtext><msub><mi></mi><mn><mtext>rest</mtext></mn></msub><mtext>) → 0, </mtext><mtext>and</mtext><mtext> </mtext><mtext>2RT</mtext><mtext>F</mtext><mtext> </mtext><mtext>at</mtext><mtext> E → E</mtext><msub><mi></mi><mn><mtext>crit</mtext></mn></msub></math>. The cathodic Tafel slope is <math><mtext>2RT</mtext><mtext>F</mtext></math>. These results, including their pH dependence, are explained with a reaction mechanism involving the participation of adsorbed hydroxo-species.